Alfresco Software says freeloading corporations led them to closed-source strategy

Alfresco Software said Tuesday it will not release certain new enterprise features of the Alfresco content management products, such as high-availability clustering, as open source as a way to persuade freeloading companies to pay up. John Newton, CTO and co-founder of Alfresco Software Inc., posted notice of this new business strategy in a blog entry that effectively says Fortune 50 users of the free version of Alfresco are cheapskates. He reassures everyone in his blog that core components of Alfresco will remain open source and free. Alfresco thus joins other commercial open source projects, such as MySQL, in bifurcating their source code into a core version licensed as open source, and a version with features important to large businesses (the ones with money) available for a fee.

In a blog last August, Andrew Lampitt called this division an "open-core licensing" model. This division is now officially reflected in Alfresco Software's release Tuesday of Alfresco Enterprise 3.1.

Newton implied in his blog that Alfresco Software was pushed to close-source enterprise features of Alfresco for financial reasons. Many "world-class companies" with "household brands" are using Alfresco's free and open source Labs version, he wrote, and not paying the annual Enterprise subscription. Enterprise subscriptions are a source of revenue for Alfresco Software. Subscribing customers receive a more stable "Enterprise Edition" of the Alfresco content management suite, dedicated support, and optional training and consulting. By releasing enterprise features of Alfresco only to paying customers, Newton said, he hopes Alfresco's largest users will see the benefit of paying Alfresco an annual subscription rather than paying their own developers to figure out how to deploy Alfresco in a high-availability environment or writing their own management tools.

If indeed Alfresco Software won't be able to survive (or at least thrive) without finding a more sustainable revenue source, this move sounds like a good strategy. It will allow Alfresco to continue to improve its already excellent enterprise content management system while allowing smaller companies to use Alfresco's core products for free. If, however, this bifurcated source code strategy is merely a way to return higher profits to Alfresco's founders and funders, the change might negatively impact how Alfresco Software is perceived by developers writing useful extensions and integrations and releasing them as free, open source. Open source developers release their code for the community's benefit as a whole, but might hesitate to do so when a corporation profits indirectly from their work.

There is nothing wrong with a corporation out to make money, and adopting the "open core" model might be the best move for Alfresco's future -- as a product and as a company. I don't know whether much or any of the Alfresco "core" code base was written by non-Alfresco employees. If not, the risk of Alfresco losing contributions from external open source developers is small. Other "community" contributions, like free technical support offered by fellow users on the Alfresco forums, likely will continue unaffected by the licensing change because much of that free exchange of information is among users of the free Labs version.

From what the privately held Alfresco Software says publicly, it isn't hurting for money. Alfresco employees I spoke with last year say the company is profitable. Matt Asay, Alfresco's vice president of business development, said in a CMS Wire story Tuesday by Barb Mosher that sales have been increasing recently by more than 27% from the quarter before. On Monday, Alfresco Software released limited financial information for its fiscal year ended Feb. 28. The news release says Alfresco Software Inc. closed the 2008 fiscal year with a 103% year-over-year revenue growth and a 92% increase in revenue from the fourth quarter of 2008 compared to the same quarter in 2007. It also added 270 paying customers during the 2008 fiscal year.

Newton wrote in his blog that Alfresco Software looked at options other than close-sourcing enterprise features. Alfresco considered "crippling" the open source version, he said, or letting the open source branch become so cutting-edge that it fell "into a destabilized state." But going that route "would make it difficult for certain governments to use our product," he said, and could cause the open source community to create competing forks to fix the crippleware.

Newton said Alfresco's new software model will adhere to these six principals:
  1. Alfresco extensions to create high-availability, clustered systems and provide better monitoring and and administration will be developed as closed source.
  2. The core system and interfaces will remain 100% open source.
  3. Bugs fixed for Enterprise customers will be folded into the next open source Labs release.
  4. Code that Alfresco Software writes for paying customers to integrate Alfresco with proprietary systems will remain closed source.
  5. Integrations to "ubiquitous" proprietary systems, like SharePoint, will remain open source.
  6. Alfresco will continue to support paying customers to the levels of their SLAs.


Installing Groovy from RPM on Fedora

I installed Groovy 1.6 on Fedora from an RPM as offered on the Groovy download page and immediately got an exception stack trace when running groovysh or groovyConsole. I installed the groovy-1.6.0-2.noarch.rpm file, kindly packaged by Federico Pedemonte, then tried to run groovyConsole:
[tom@dev ~]$ groovyConsole
Exception in thread "main" java.lang.NoClassDefFoundError: org/codehaus/groovy/tools/GroovyStarter
Caused by: java.lang.ClassNotFoundException: org.codehaus.groovy.tools.GroovyStarter
at java.net.URLClassLoader$1.run(URLClassLoader.java:200)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:188)
at java.lang.ClassLoader.loadClass(ClassLoader.java:307)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
at java.lang.ClassLoader.loadClass(ClassLoader.java:252)
at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:320)
Could not find the main class: org.codehaus.groovy.tools.GroovyStarter.  Program will exit.
I then tried to run groovysh with no better luck:
[tom@dev ~]$ groovysh
Exception in thread "main" java.lang.NoClassDefFoundError: org/codehaus/groovy/tools/GroovyStarter
Caused by: java.lang.ClassNotFoundException: org.codehaus.groovy.tools.GroovyStarter
at java.net.URLClassLoader$1.run(URLClassLoader.java:200)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:188)
at java.lang.ClassLoader.loadClass(ClassLoader.java:307)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
at java.lang.ClassLoader.loadClass(ClassLoader.java:252)
at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:320)
Could not find the main class: org.codehaus.groovy.tools.GroovyStarter.  Program will exit.
The problem turned out to be quite simple to solve: a missing GROOVY_HOME. The packager adds the environment variable GROOVY_HOME to the shell by adding the file /etc/profile.d/groovy.sh so bash picks it up at startup via the /etc/profile script, but my current shell hadn't had a chance to read in that file yet.

The solution was as easy as exiting and starting a new shell, or manually setting:
[tom@dev ~]$ export GROOVY_HOME=/usr/share/groovy
[tom@dev ~]$ groovyConsole
and everything works.

How to modify the Alfresco Share page footer

Share is Alfresco Software's open source collaboration server. It's a Java web application that stands as a free competitor to Microsoft SharePoint. Since I wrote earlier this month about how to modify the default footer text in the Alfresco content management server's web client, I thought I'd follow up with even simpler instructions on how to modify the global footer in Alfresco Share. You don't even need to stop and restart the web application server for this modification.

Share is part of the open source Alfresco Labs 3 and the commercial Alfresco Enterprise Edition enterprise content management server and is built using Alfresco's Surf web framework. The Share application comes fully functional out of the box (more precisely, out of the share.war file). But it also is highly customizable with a little HTML, JavaScript and FreeMarker script modifications or additions. Thus, the default footer text in Share is much easier to modify than it is in the Alfresco web client I wrote about earlier.

The web client, which is a JavaServer Faces application, embeds the footer text inside a Java tag library inside a JAR file inside the alfresco.war file. You need the source code and a JDK to modify the global footer text. The Share web application, more simply, places its footer text inside a properties file inside the share.war file, which you can customize with a plain text editor. If you deploy Share as a WAR file instead of an exploded WAR, you'll need to unzip the WAR, edit the text file, then rezip. But that's about as complex as this change gets.

To customize the footer text for Share, unzip the share.war file if necessary to a directory of your choosing or just find the exploded WAR file you have currently deployed. If you run Share on Tomcat, your deployed Share application likely is in the directory $CATALINA_HOME/webapps/share (or %CATALINA_HOME%\webapps\share under Windows). The file to modify is in the directory
WEB-INF/classes/alfresco/site-webscripts/org/alfresco/components/footer
called footer.get.properties. On my version of Alfresco Share, this default footer file looks like this (but all on one line):
label.copyright=Supplied free of charge with
<a href='http://www.alfresco.com/services/support/communityterms/#support'>no support</a>,
<a href='http://www.alfresco.com/services/support/communityterms/#certification'>no certification</a>,
<a href='http://www.alfresco.com/services/support/communityterms/#maintenance'>no maintenance</a>,
<a href='http://www.alfresco.com/services/support/communityterms/#warranty'>no warranty</a> and
<a href='http://www.alfresco.com/services/support/communityterms/#indemnity'>no indemnity</a>
by <a href='http://www.alfresco.com'>Alfresco</a> or its
<a href='http://www.alfresco.com/partners/'>Certified Partners</a>.
<a href='http://www.alfresco.com/services/support/'>Click here for support</a>.<br />
Alfresco Software Inc. © 2008-2009 All rights reserved.
This text gets rendered on every Share page as a footer that looks like this:



You can see why someone might want to change this global footer text.

Change the text to anything you like and save footer.get.properties file. Mine now says:
label.copyright=Alfresco Software Inc. © 2008-2009 All rights reserved.
To see your change, you can either restart your web application server if no one is using Share, or you can tell Share to refresh its web components cache without inconveniencing anyone currently using the server. Here's how.

Login to Share as the "admin" user and visit the service /share/service path of the Share application. If you are running Share on your Tomcat local server, the path is probably http://localhost:8080/share/service/. This page will have a button at the bottom labeled "Refresh Web Scripts". Click it, and your footer text change should be loaded the next time the footer component script is called.



Ahh. Much better.

If you build Share from source, you can make your footer text change there by making the change to the "slingshot" project. That apparently was the earlier name of the Share application. The file is config/alfresco/site-webscripts/org/alfresco/components/footer/footer.get.properties

Making this footer change might whet your appetite for making other customizations to your Share application. The Surf component framework makes customization fairly easy once you get the hang of how Surf works. By being able to see your changes quickly by interactively refreshing the web scripts rather than restarting the server, your feedback comes quickly.

How to get rid of the Alfresco Labs default page footer

The web client for the open source Alfresco enterprise content management server ships with a footer that is added to every webpage via a JSP tag. The footer blends marketing and usage tracking with a copyright statement. It can be annoying to see on every page, especially if you are using the web client internally. The web client footer looks like this (from a clipped screen capture):

Alfresco page footer image

The footer says:
Supplied free of charge with no support, no certification, no maintenance,
no warranty and no indemnity by Alfresco or its Certified Partners. Click
here for support. Alfresco Software Inc. © 2005-2009 All rights reserved.
The footer includes Alfresco's logo by reading an image from the Alfresco website. This image is called a web bug, or beacon, and Alfresco can use the image request to their server to help track who is using Alfresco. The footer's underlined text links to pages on the alfresco.com website to provide warnings that the Labs version of Alfresco is not supported by Alfresco Software Inc. The right-side graphic links you to Alfresco's SourceForge download site.

Except for the web beacon image, I don't fault Alfresco Software for adding the footer to its web client. Alfresco Labs is a powerful -- free -- and flexible product. If used within an organization, it is not a bad thing that users are made aware that the product is not the supported Enterprise version. However, since I am using Alfresco on an internal website, and plan to customize the various JSP pages, displaying the warning on every one of my pages seems overkill and unnecessary. And I could do without sending tracking statistics to Alfresco Software.

Removing the global footer isn't a simple process, but it is pretty straightforward. The removal should be as simple as editing a globally included text file. Instead, those clever developers at Alfresco embedded the footer text into a fairly useful JSP tag. This <r:page> JSP tag outputs the skeletal HTML page tags, and includes HTML to pull in global scripts and cascading stylesheets. It also includes code that can log how long it took Alfresco to build the JSP page. To remove the footer from your web pages, you need either to stop using the r:page tag or recompile the page tag to set the text to what you would like, which is what the instructions below cover.

Recompiling the r:page tag that lives in the Alfresco web client JAR file isn't complicated. Assuming you already are using the Alfresco Labs 3 web application, the process should take you a half hour or less, with most of that time spent downloading and compiling code.

Overview

The steps below show you how to obtain the complete source code to Alfresco, make the necessary change to the Java page tag code, rebuild the web client JAR file, then replace the existing JAR file in your Alfresco server with the newly built one.

Prerequisites: You must have a Java compiler, a Subversion client, Apache Ant, and be able to use the command line. For Windows users without Subversion, you can install the SlikSVN client. Others can find a link to download a Subversion client from CollabNet's Tigris.org.

Instructions

Here are the steps to rebuild the Alfresco web client with the altered JSP page tag. (You should be able to cut and paste these lines onto your command line if you remove the prompt character.)
  1. Create an empty directory for the source code
    % mkdir alfresco-labs
    % cd alfresco-labs
    
  2. Use Subversion to download the Alfresco Labs source code
    % svn co svn://svn.alfresco.com/alfresco/HEAD
    
    or use the http protocol if you have internal firewall issues:
    % svn co http://svn.alfresco.com/repos/alfresco-open-mirror/alfresco/HEAD
    
    The svn command will connect to the Alfresco Subversion repository and copy each of the files in the HEAD branch into your local directory. Total download size will be about 734MB. Depending on the speed of your connection, this might be a good time to get coffee, have lunch, check your email. If the Subversion URL doesn't work, check this page to see if Alfresco has changed the repository location.

  3. Edit PageTag.java to change/remove the page footer text
    The PageTag.java file you want to edit is in the directory HEAD/root/projects/web-client/source/java/org/alfresco/web/ui/repo/tag. The commands below will edit the file in Notepad for Windows or vi for Unix/Mac users. But you also can just navigate to the folder and edit the file with any editor.

    For Windows:
    % notepad HEAD\root\projects\web-client\source\java\org\alfresco\web\ui\repo\tag\PageTag.java
    
    For Unix variants:
    $ vi HEAD/root/projects/web-client/source/java/org/alfresco/web/ui/repo/tag/PageTag.java
    
    At this point, you can decide what you want your new page footer text to say. The quickest edit is to completely remove all footer contents by changing line 115:
    private static String alfresco = null;
    
    to:
    private static String alfresco = "";
    
    Why this works is that static alfresco variable holds the contents of the page footer HTML (images and text), which is output by the overridden JSP tag library method doEndTag. If the alfresco variable is null, which it is the first time the code is run, the doEndTag method calls a private helper method, getAlfrescoButton, to populate it.

    If you want to change the footer text to something of your own choosing, or perhaps you want to retain the Alfresco copyright notice because you won't be changing the web client's look and feel, you will want either to set the alfresco variable to the text of your choosing, or edit the getAlfrescoButton method and/or some of the variables it uses to build up the footer text.

    For example, if you want to retain the copyright statement but remove the warning text, edit the ALF_COPY constant on lines 103-112 to remove the text you don't want:
    private final static String ALF_COPY  = "Supplied free of charge with " +
    "<a class='footer' href='http://www.alfresco.com/services/support/communityterms/#support'>no support</a>, " +
    "<a class='footer' href='http://www.alfresco.com/services/support/communityterms/#certification'>no certification</a>, " +
    "<a class='footer' href='http://www.alfresco.com/services/support/communityterms/#maintenance'>no maintenance</a>, " +
    "<a class='footer' href='http://www.alfresco.com/services/support/communityterms/#warranty'>no warranty</a> and " +
    "<a class='footer' href='http://www.alfresco.com/services/support/communityterms/#indemnity'>no indemnity</a> by " +
    "<a class='footer' href='http://www.alfresco.com'>Alfresco</a> or its " +
    "<a class='footer' href='http://www.alfresco.com/partners/'>Certified Partners</a>. " +
    "<a class='footer' href='http://www.alfresco.com/services/support/'>Click here for support</a>. " +
    "Alfresco Software Inc. © 2005-2009 All rights reserved.";
    
    If you want to keep some of the text but remove the web beacon image or SourceForge graphic, you will need to edit the getAlfrescoButton method or set the alfresco variable as discussed previously.

    Fortunately, the getAlfrescoButton method does not add structural HTML text to the footer, so setting the alfresco variable directly with your chosen text is a viable option. If you use HTTPS on your website and you want to use an image in your footer, have a look at the technique used in the getAlfrescoButton method to change the image URL based on the request scheme. It's a handy way to avoid having web browsers complain about an encrypted page using non-encrypted components.

    With the code edited, you are ready to rebuild Alfresco.
  4. Rebuild the web client application
    Here is where you need Ant. Use the build target to rebuild the project modules. The default target will attempt to deploy the rebuilt WAR file, so make sure to use the "build" target.

    For Windows:
    % ant -f HEAD\root\build.xml build
    
    For Unix:
    $ ant -f HEAD/root/build.xml build
    
    You will see several warnings about the use of deprecated methods and the like. But the code should build correctly.

    The Ant task should rebuild the Alfresco JAR files and the WAR file. The rebuilt alfresco-web-client.jar file is the one that contains the repository JSP tag you want to replace. The Ant task creates this JAR file in the directory HEAD/root/projects/web-client/build/dist.
  5. Copy the alfresco-web-client.jar to your Alfresco webapp
    Copy the JAR file to your exploded WAR file directory location under the WEB-INF/lib directory. If you deploy Alfresco as WAR file rather than exploded WAR, you can use the full alfresco.war file that you also will find in the HEAD/root/projects/web-client/build/dist. directory.
You're done. You should now be able to restart your application server and visit your Alfresco website:

Alfresco page without footer

Gone is the footer from this and all Alfresco web client pages.

Weighing risks of storing files in a content management system

I was cleaning out a desk drawer last weekend and found a few old 3 1/2 inch floppy disks. The discovery made me realize that in order to read the data off those disks, I would have to pull the floppy drive from an old computer and install it in a functioning computer -- and hope the new computer had the appropriate data connector, or that I could find an adapter.

The discovery of the floppies, and the realization that the data couldn't easily be read, is parallel to a situation I face today as I debate moving my document and media files to a content management system. The risk today, just like with the floppy disks, is that I might end up storing important data in a format that later becomes unreadable.

I have been contemplating moving a bulk of my personal text files, and perhaps even multimedia files, to an Alfresco CMS running on my home server in order to access my documents conveniently from anywhere. I have been using Evernote to store text notes and web clips, and I looked at Google Docs as an option. Both are great services and dead-simple to manage, but these online services don't provide some of the conveniences of Alfresco.

Alfresco is a free, open source Java web application that is slowly becoming a Swiss army knife for managing content. One of Alfresco's compelling features is the wide variety of file-access protocols it offers to manipulate documents stored in its repository. Alfresco's documents can be accessed via its web client, Java APIs, and CMIS, sure. But more interesting for my current needs is that documents stored in Alfresco also can be read, written and deleted from other computers on the LAN using a CIFS/SMB shared drive, over the web using WebDAV, using NFS, and even FTP.

Because Alfresco can expose its managed content using so many industry-standard protocols, I thought storing my files inside Alfresco would make it easier for me to access my documents no matter where I was, without adding the need for a specialized client application or web connection. I could use a CIFS shared drive at home to access documents from any of my home computers. I could access the documents securely from work using WebDAV over SSL. And I could access documents from a friend's house by logging into my home server from a web browser using Alfresco's native web application. My documents would be stored at home, but also available "in the cloud." I could even use Alfresco's feature to emulate a SharePoint server to version and share my MS Word and other Office documents from Office applications.

Making my documents this accessible would be convenient and (on the geeky side of) cool. I do have a strong concern about whether I want to risk exposing my documents to Internet hackers. But the longer term concern is will I find myself wanting to access my files someday without using Alfresco? Will my content repository one day become the equivalent of a floppy disk?

The risk of storing data in a format that later becomes unreadable is not new, and the problem grows as more of our lives become digitized. I remember a few years ago hearing Grady Booch describe his work preserving seminal software for the Computer History Museum and his labor of love, the Handbook of Software Architecture. He mentioned that software that should be preserved for historical and educational reasons is sometimes stored in once-popular paper or magnetic formats that are difficult to read today. The Library of Congress has been concerned with what digital formats it should use in order to store its electronic archives.

Alfresco stores its content as regular files, which is good. However, those files are named using globally unique identifiers rather than the original file name. The stored documents are mixed with other files used by Alfresco for versioning and other purposes in a series of numbered subdirectories. Do I want to rely on Alfresco being the required middleman to give me the files I need? Using the digital media sustainability factors used by the Library of Congress to rate digital preservation, I would rate Alfresco's storage like this, with High meaning good for sustainability:
  • Disclosure: High
    The files are stored in your native format like ext3 or NTFS. Alfresco itself is open source, and it runs under Java, which can be run on nearly any modern operating system.
  • Adoption: Low
    Despite Alfresco being powerful and free, the file organization and metadata formats are unique to Alfresco.
  • Transparency: High
    Alfresco stores files as regular files, albeit buried within its own directory organization scheme, and the file metadata is stored in a relational database of your choosing.
  • Self-documentation: Low
    Alfresco separates file contents from its metadata using a proprietary storage scheme. Reuniting the two requires Alfresco.
  • External dependencies: Medium-to-High
    Retrieving file data with its metadata requires Java, a web application server, Alfresco, and the database used to store the metadata. Since I use the open source MySQL as my database, and all other dependencies are open source, the external dependencies can be easily assembled. But it would be a pain.
  • Impact of patents: High
    I think all the technology needed to retrieve the data is unencumbered by patents.
  • Technical protection mechanisms: High
    Alfresco's files are stored on the file system without alteration, so no translation or decryption is needed.
Overall, Alfresco scores well for sustainability. The data should be retrievable for the foreseeable future by anyone properly motivated. However, its low Self-documentation and Adoption scores concern me. For example, say a fire completely destroys our home. While we run outdoors, my wife wisely remembers to grab my external backup USB drive. That hard drive -- hopefully -- contains a backup of the Alfresco repository file system and the Alfresco MySQL database containing the content repository metadata, like file name, file path, date created. Whew! My data are safe.

But, hmm, how to find that fire insurance policy while I'm at the local motel's shared lobby computer. Yes, it will be possible to find the file I need through search tools, or by opening the files one by one -- and in the case of binary image files, by changing the file extension from Alfresco's ".bin" to whatever format the file really contains so I can open it with the proper application. But getting my files out of the Alfresco repository, with the file name and directory structure with which the files are usable, will not be as easy as plugging the disk drive into someone else's computer and opening the file with a text editor. It will be in unexpected situations like this when I will have wished I had kept my files stored as regular files in regular directories and just used Samba.

That's where I am now, weighing the advantages of storing my files in a content management system versus the disadvantages and risks. I'm guessing many businesses go through this same struggle whenever they adopt a content management system for their documents. Once a company switches to a content management system, they must jump in with both feet and live with the benefits and problems of storing their documents inside an electronic vault controlled by a piece of non-standard software. At least with Alfresco, the process is reversible through its CIFS interface, and less scary because of its open source nature.

Maybe my solution will be to use Alfresco but to backup my content repository using the CIFS interface. That way, my backups are independent of Alfresco and I preserve the files with their original names and directory locations. I'd lose any extra Alfresco metadata stored with the files, any versioning, any software triggers or rules associated with the files. But I'd still enjoy Alfresco's benefits on my live file system. If you have faced and solved a similar situation when using a content management system, your comments are welcome.

Finally got Tomboy working in Fedora 10

After installing Fedora 10 last month, I finally got the Tomboy note-taking application working. I began using Tomboy in Fedora 8, and have several notes stored in Tomboy notebooks. When Tomboy broke in Fedora 10, I put it on my to-do list to figure out how to get it working. I figured the fix would be as easy as re-installing Tomboy. It wasn't.

Fedora 10 was released three months ago tomorrow. That's why I was surprised to find that reinstalling / upgrading to the latest Tomboy from the Fedora repository didn't fix the bug. Before I fixed the problem, trying to run Tomboy would give me an error like:
** (Tomboy:4816): WARNING **: The following assembly referenced from
/usr/lib/tomboy/Tomboy.exe could not be loaded:
Assembly:   Mono.Addins    (assemblyref_index=8)
Version:    0.3.0.0
Public Key: 0738eb9f132ed756
The assembly was not found in the Global Assembly Cache, a path listed in the
MONO_PATH environment variable, or in the location of the executing assembly
(/usr/lib/tomboy).
Until I saw the error, I didn't even know Tomboy was a .NET application running under Mono. I searched around for a solution to the problem and found the bug has been reported three times to Red Hat Bugzilla, but still no one has solved it. The solution, fortunately, was pretty simple, and was mentioned by Austin Acton in a bug comment. The solution also was mentioned on this blog post by Mark Ito (I'm assuming that's his name from the subdomain).

The solution is to install mono-addins from the 'fedora' repository.
sudo yum install mono-addins
For such an easy fix, you have to wonder why this 5-month old bug with high severity is still open. Tomboy comes as part of the standard Fedora 10 install. It must not be as easy as making the tomboy package dependent on the mono-addins package.

Installing Sun Java JDK 6 Update 12 on Fedora 10

When I set out to install Sun's latest Java development kit on my newly upgraded Fedora 10 development box, I discovered the previous instructions I had used on Fedora 8 from the Fedora FAQ no longer cover installing the Sun JDK. The instructions now refer only to OpenJDK using the java-1.6.0-openjdk package. After a short search, I found a newer installation technique, but unfortunately had to tweak it because it didn't work with JDK 6u12.

The best instructions I found for installing the Sun JDK on Fedora were from Fedora developer Paul Howarth at www.city-fan.org/tips/SunJava6OnFedora. Paul's instructions and his modified jpackage Java 6 RPM package are fantastically helpful. He details how to custom-build Java installation RPMs by rebuilding his RPM with the Sun Microsystems Java 1.6 "bin" installer.

The only roadblock to success was that Paul built his RPM for Java 6 update 7. The RPM spec file doesn't work if you run it with Sun's latest (as of this writing) jdk-6u12-linux-i586.bin file. My first attempt to follow Paul's instructions got me this:
[tom@development Download]$ rpmbuild --rebuild java-1.6.0-sun-1.6.0.7-1.1.cf.nosrc.rpm
Installing java-1.6.0-sun-1.6.0.7-1.1.cf.nosrc.rpm
warning: InstallSourcePackage at: psm.c:246: Header V3 DSA signature: NOKEY, key ID b56a8bac
warning: user paul does not exist - using root
warning: group paul does not exist - using root
warning: user paul does not exist - using root
warning: group paul does not exist - using root
warning: user paul does not exist - using root
warning: group paul does not exist - using root
Executing(%prep): /bin/sh -e /var/tmp/rpm-tmp.W96jt0
+ umask 022
+ cd /home/tom/rpmbuild/BUILD
+ LANG=C
+ export LANG
+ unset DISPLAY
+ rm -rf /home/tom/rpmbuild/BUILD/jdk1.6.0_07
+ export MORE=10000
+ MORE=10000
+ sh /home/tom/rpmbuild/SOURCES/jdk-6u7-linux-i586.bin
sh: /home/tom/rpmbuild/SOURCES/jdk-6u7-linux-i586.bin: No such file or directory
error: Bad exit status from /var/tmp/rpm-tmp.W96jt0 (%prep)
The warnings are harmless. But as you can see, during the "prep" stage, rpmbuild is expecting the bin file to be called jdk-6u7-linux-i586.bin instead of the bin file for update 12. I optimistically hoped I might be able to get around this snag by renaming the newer file to the older name:
[tom@development Download]$ mv ~/rpmbuild/SOURCES/jdk-6u12-linux-i586.bin ~/rpmbuild/SOURCES/jdk-6u7-linux-i586.bin
But that just got me one step farther:
[tom@development Download]$ rpmbuild --rebuild java-1.6.0-sun-1.6.0.7-1.1.cf.nosrc.rpm
Installing java-1.6.0-sun-1.6.0.7-1.1.cf.nosrc.rpm
warning: InstallSourcePackage at: psm.c:246: Header V3 DSA signature: NOKEY, key ID b56a8bac
warning: user paul does not exist - using root
warning: group paul does not exist - using root
warning: user paul does not exist - using root
warning: group paul does not exist - using root
warning: user paul does not exist - using root
warning: group paul does not exist - using root
Executing(%prep): /bin/sh -e /var/tmp/rpm-tmp.1AYQKX
+ umask 022
+ cd /home/tom/rpmbuild/BUILD
+ LANG=C
+ export LANG
+ unset DISPLAY
+ rm -rf /home/tom/rpmbuild/BUILD/jdk1.6.0_07
+ export MORE=10000
+ MORE=10000
+ sh /home/tom/rpmbuild/SOURCES/jdk-6u7-linux-i586.bin
+ cd /home/tom/rpmbuild/BUILD
+ cd jdk1.6.0_07
/var/tmp/rpm-tmp.1AYQKX: line 33: cd: jdk1.6.0_07: No such file or directory
error: Bad exit status from /var/tmp/rpm-tmp.1AYQKX (%prep)
The rpmbuild was able to find and run Sun's (renamed) shell script, but then failed when it tried to switch to the non-existent jdk1.6.0_07 directory in BUILD.

To solve the problem, I had to edit the RPM "spec" file and make two small changes to account for the updated version. Then I continued with Paul's instructions, except using the modified spec file in place of directly using his RPM file. I got the idea of editing the spec file from a blog posting by Nick Lothian.

Here are my modification's to Paul's instructions,
  • Follow Paul's instructions up to and including running the rpmbuild command under the section "Build Java RPM Packages."

  • Begin Detour: After you get the error (shown above) that says "jdk-6u7-linux-i586.bin: No such file or directory," you won't have the RPM files but you will have an RPM spec file stored in ~/rpmbuild/SPECS, called java-1.6.0-sun.spec.

  • Edit this ~/rpmbuild/SPECS/java-1.6.0-sun.spec file by:
    Changing this line (line 37 in my spec file):
    %define buildver        7
    
    to say:
    %define buildver        12
    
    so the buildver is 12 instead of 7, and changing this line (line 45 in my spec file):
    %define toplevel_dir    jdk%{javaver}_0%{buildver}
    
    to say:
    %define toplevel_dir    jdk%{javaver}_%{buildver}
    
    That is, remove the "0" (zero) right before the %{buildver} variable. That second change stumped me at first because Paul apparently had to add a zero-padding in the directory name to get "07" when he was working with Update 7.

  • Run rpmbuild again by using the spec file instead of the rpm file using this command:
    [tom@development Download]$ rpmbuild -ba --rebuild ~/rpmbuild/SPECS/java-1.6.0-sun.spec
    
    This command should succeed with building new RPMs for Sun's JDK.

  • End Detour. Continue with Paul's instructions under "Remove Any Old Cruft."
Now that I have the Sun JDK installed, I'm am curious whether I can find situations where OpenJDK performs differently from Sun's JDK. Thanks to the handy "alternatives" Linux command that lets me easily switch between the different JDK versions, I'll be able to test my Java applications within both environments. After a sudo alternatives --config java, I have:
[tom@development ~]$ java -version
java version "1.6.0_12"
Java(TM) SE Runtime Environment (build 1.6.0_12-b04)
Java HotSpot(TM) Server VM (build 11.2-b01, mixed mode)
Success.

The terribly misunderstood super()

For developers new to Java, here's a tip that could make you look more like a ninja coder than colleagues who have been writing Java for years: learn how super() works within constructors.

I say this because I recently completed a yearlong project with 12 developers and found during the staffing process that about one third of the developers I interviewed, many of whom had been coding Java professionally for years, misunderstood fundamental concepts of Java object creation. Some of these smart developers would insist during the job interview that unless a Java constructor explicitly invokes super(), the parent constructor would never be called. With such an important Java language feature being so terribly misunderstood, I thought I'd dust off this blog with a reminder to those new to Java of how super() works in constructors. A related topic would be how this(...) works, but I'll leave that for another time.

Rule: You never, ever, have to call the no-argument super().

Corollary: It is impossible to instantiate an object without at least one constructor being invoked in all parent classes.

With this rule in mind, here is code to illustrate.
public class A {
public A() {
System.out.println("A says hello");
}
}
public class B extends A {
public B() {
System.out.println("Hello from B");
}
}
If you instantiate class B like this:
B myB = new B();
the console will output:
A says hello
Hello from B
Since B's constructor didn't specify a different constructor in class A by using super with an argument list, the Java runtime invoked A's no-argument constructor by default. No call to super() is needed from within B's constructor in order for the A parent class to be instantiated. In fact, there is absolutely, positively no way to create a B instance without creating an A instance first.

If I modify class B to add super():
public class B extends A {
public B() {
super();
System.out.println("Hello from B");
}
}
the output would be identical to the first version. In fact, the generated Java bytecode would be identical. When there is no explicit call to super() as the first statement in a constructor, the Java compiler implicitly adds a call to the no-argument super() to invoke the no-argument constructor of the parent class. There is never a need to add an explicit call to a no-argument super().

I think a lot of Java developers end up believing you need to call super() in order for the superclass's constructor to be called because so much Java code out there includes extraneous calls to super(). For instance, here is a constructor taken verbatim from a Hello World J2ME coding example from Research in Motion Ltd., the makers of the BlackBerry smart phones.
//create a new screen that extends MainScreen, which provides
//default standard behavior for BlackBerry applications
final class HelloWorldScreen extends MainScreen
{
public HelloWorldScreen()
{
//invoke the MainScreen constructor
super();
//add a title to the screen
LabelField title = new LabelField("HelloWorld Sample", LabelField.ELLIPSIS
| LabelField.USE_ALL_WIDTH);
setTitle(title);
//add the text "Hello World!" to the screen
add(new RichTextField("Hello World!"));
}
If I were a developer just learning Java, I would assume the call to super() is required in order to invoke the parent class's constructor. Why else would the HelloWorldScreen developer code it, and add that comment to explicitly point out the call to the parent class? I searched Krugle for open source projects using calls to the no-argument super() and found 82,347 Java files, including code from major projects like Eclipse and GlassFish. It seems many developers like explicitly invoking super().

I can see one possible reason for doing so. Perhaps there are several constructors in the parent class and the developer wants to call out that he or she is using the no-argument version. The first danger I see with adding extra code that adds no behavior to a program is the risk of adding confusion. For instance, I recently ran across code with constructors that looked something like this:
public class SpecialClass extends RegularClass {
private int x, y;
public SpecialClass() {
super();
}
public SpecialClass(int x) {
super();
this.x = x;
this.y = 0;
}
public SpecialClass(int x, int y) {
this.x = x;
this.y = y;
}
}
The first two constructors explicitly called super(), but the third constructor didn't. Was that a mistake? Did the developer mean to add a call to a different superclass constructor, like super(x, y), but forgot? If not, why did he leave off the third call to super()?

Finding small inconsistencies in code like this waste development time as the reader tracks down whether the inconsistency was the result of harmless oversight or the result of an error that is now a bug. Code that doesn't do anything, without a documented reason for being there, seems way more hazardous to understanding code than any value I can see that might be gained from "documenting" that you really meant the automatic behavior to be taken by writing extra code. Similar to seeing a class that extends java.lang.Object, I end up asking why did the developer do that.

(If you use super() regularly for documentation purposes, I would appreciate hearing your reasons.)

The second danger in adding extraneous calls to super() is that it seems to be teaching a lot of new Java developers that super() is required in order for parent constructors to be invoked. At least that certainly is my recent experience from interviewing Java developers.

The only time super is required is when it takes a non-empty argument list to invoke a constructor in the parent class that requires parameters. For example, here is my base class to represent a knight from the movie Monty Python and the Holy Grail. Note that the constructor requires an argument.
public class EnglishKnight {
private String whatISay;
public EnglishKnight(String saying) {
whatISay = saying;
}
@Override
public String toString() {
return whatISay;
}
}
This following subclass (with an error) is meant to be a certain kind of knight from the movie:
public class KnightWhoSaysNeep extends EnglishKnight {
public KnightWhoSaysNeep() {
// syntax error here.
}
}
You probably see the compile-time error. Since KnightWhoSaysNeep extends EnglishKnight, and since EnglishKnight does not contain a no-argument constructor, the KnightWhoSaysNeep class must override the implicit (and illegal) call to super() in its constructor. Here's the error from Eclipse:
Implicit super constructor EnglishKnight() is undefined.
Must explicitly invoke another constructor
To fix KnightWhoSaysNeep we need to call one of the valid constructors in the superclass. In this case, there is only one constructor in the superclass, which takes a String as an argument.
public class KnightWhoSaysNeep extends EnglishKnight {
public KnightWhoSaysNeep() {
super("Neep!");
}
}
The corrected KnightWhoSaysNeep class demonstrates the proper use of super -- one that takes a parameter to override default behavior.

Koen Aers jBPM EclipseWorld sneak preview

Even though Koen Aers from JBoss had to be up early Thursday to give a jBPM presentation at EclipseWorld 2007, he kindly stopped by our Northern Virginia Java Users Group (NovaJUG) meeting Wednesday night to talk about business process management in general and JBoss's jBPM platform specifically.

Koen Aers presents at NovaJUG
Koen Aers presents on jBPM at
the NovaJUG meeting Nov. 7.
[photo from my phone]
JBoss jBPM is an open source business process management platform that helps separate business processes and tasks from the rest of the business logic. The platform defines a process definition language, and provides a Java library to execute and persist the business processes. It can be used in a standard Java SE application as well as deployed to servlet containers -- not just JBoss Application Server.

Business process engines can make applications easier to write, but they have received a bad reputation, Aers said. The reputation stems from the fact that most business process management systems are behemoths that take up half your hard disk and come with a steep learning curve, he said. JBPM is about a 500KB core library, not counting its Hibernate database persistence layer, and developers can learn and use only a small part of the whole platform.

BPM engines don't need to be complex. At their core, he said, business process engines boil down to the management of state: what state is each instance of a business process in at the moment, and what internal or human activities trigger a transition to a new state.

Here are my notes from Koen Aers's jBPM presentation.

Why use a process language?
  • Simplify an application by extracting the state-management logic.
  • Improves communication: Process languages should support graphical modeling that maps to executable notation.
  • Automatic persistence history can be used for business intelligence.
What is a Business Process Management System?
  • A tool that allows an analyst to model workflows (business processes) and hand over results to a developer, who will add the details to make it executable.
  • With modeling, the more expressive the modeling notation, the harder it is to make the model executable.
  • Thus the choice of modeling notation is important.
    Popular modeling notations:
    BPMN: a pure modeling notation. No automatic translations to code.
    BPEL: The purpose is to orchestrate web services and publish result as a new web service.
    XPDL: A format for storing process models.
  • A big repository that holds executable processes, persists the execution state of the processes, and records history of what happened during the process executions.
JBoss jBPM uses its own notation, called jPDL. The jBPM architecture was built to add a "process virtual machine" on top of the Java VM. It would be responsible for executing the processes stored in jPDL, BPEL, XPDL, a web page-flow language or any similar language that defines a process flow. However, currently the engine supports only JBoss's jPDL. Bull is working to add XPDL support to jBPM using Bonita, which should be released under an LGPL license next year, Aers said.

JPDL is an XML language defined by a schema. The language is extensible to support custom business processes. The language also supports defining Java actions that can be invoked at numerous points as the business process changes states.

Aers showed a demo of coding a business process using JBoss's visual process designer, an Eclipse plugin. The plugin lets you edit the jPDL both as XML and visually. Aers is a developer for the designer tool.

Before he started working on the jBPM designer tool, Aers said, he would code jPDL using straight XML with an editor that supported auto-completion from the XSD. The designer is primarily a marketing tool, he said, to support people's expectations of what a powerful BPMS must provide. "If you go to a presentation and you don't have a [graphical] designer, then you suck" in the customer's view, he said.